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RASPA3 => Input files and parameters => Topic started by: Riyaz on February 16, 2026, 07:49:12 AM

Title: How to calculate henry's constant of a flexible cyclic molecule in RASPA?
Post by: Riyaz on February 16, 2026, 07:49:12 AM
I am a beginner trying to calculate Henry's constant of Hexamethylcyclotrisiloxane using RASPA. First, I am calculating the Ideal gas Rosenbluth weight. I get an error saying "Multiple previous beads". I am using a united-atom force field for siloxane developed by Chng. Sholl. I have attached the molecule definition file and simulation input file.
I don't know how to instruct the software to carry out CBMC or CFCMC for the siloxane. In the RASPA manual, the examples are shown mostly for small molecules.
If I consider the bond length fixed and the Harmonic bend and OPLS torsion, should I give atom coordinates in the molecule definition file?
Should I give the force constant in kJ/mol or K?
Why am I getting this error? Is there any problem with the definition of the connectivity?
Please somebody reply! Please reply prof.Dubbledam  simulation.txtD3.txt